Technical Field of the Disclosure
The present embodiment relates in general to mounting systems for photovoltaic (PV) modules on roof structures. More specifically, the present disclosure relates to a rail-less photovoltaic (PV) module mounting system for providing a cost-effective means to install a plurality of photovoltaic (PV) modules on a roof structure.
Description of the Related Art
With the increased use of photovoltaic (PV) roofing systems for generating electricity, a demand for mounting hardware, which attaches frames for the purpose of installing the PV modules to the roof structure or any other support structure, has been developed. In recent years, various kinds of mounting structures have been used which allow the installation of PV modules to the roof structures. Mounting structures come in a variety of sizes and patterns to meet installation purposes. However, most of the mounting structures require increased labor time and cost for installation of the PV modules on the roof structures.
Conventional mounting structures for supporting PV modules in frames have considerable drawbacks. For example, many mounting structures utilize rails to mount the PV modules to the roof structure to form a PV array. The use of these rails requires additional materials to support the PV modules. Because of use of the additional material, these traditional mounting structures can result in excess shipping costs. They can also limit the PV array layout possibilities and dramatically increase the time for designing, engineering and installing the mounting structures. Existing devices are expensive, difficult to use and can require additional manpower to install. For example, a typical 5 kW PV mounting system designed to mount 20 PV panels (15.37% efficient) mounted on a traditional rail mounting system requires approximately 302 parts at a total cost of $0.69/W retail for the mounting structure only and weighs over 300 Lbs. Typical installation times for a simple 4×5 (4 rows and 5 columns) PV module rail based mounting system are approximately 49 man-hours.
Traditional rail mounting systems require 5 penetrations per mount, 4 mounts per PV module, additional grounding lugs, and requires specifically engineered PV modules. In addition, existing rail mounting systems may have substandard waterproofing for roof penetrations, along with complex grounding, wire management, and increased labor time on the roof structure due to design flaws. Hard and soft balance of system (BOS) may include bypass diodes, blocking diodes, solar controller, wiring system, battery and/or inverter etc. The hard and soft balance of system (BOS) costs for PV rail mounting system are high due to high material costs as well as long system engineering and installation times. Also, the traditional rail mounting systems require long strings that are difficult to break up, causing difficulty in working around roof obstructions (e.g. vents, skylights).
One of the existing mounting systems describes an integrated module frame and racking system for a solar panel. The system comprises a plurality of solar modules and a plurality of splices for coupling the plurality of solar modules together. The plurality of splices provide a way to make the connected modules mechanically rigid both during transport to the roof and after mounting for the lifetime of the system; provide wiring connections between modules; provide an electrical grounding path for the modules; provide a way to add modules to the panel; and provide a way to remove or change a defective module. Connector sockets are provided on the sides of the PV modules to simplify the electrical assembly when the PV modules are connected together with splices. However, the frame of the PV module is installed with a groove to attach the mounting bracket and a hole to insert the splice to connect the PV modules, which results in a labor-intensive operation. In addition, it requires one mounting bracket per PV module and multiple holes in the roof structure are required for installation, increasing the risk of leaks.
Another existing mounting system discloses a photovoltaic (PV) module framing and coupling system which enables the attachment of PV modules to a roof or other mounting surface without requiring the use of separate structural support members. The system provides a parallel coupling for securely interlocking the outside surfaces of parallel frame members together in a side-to-side arrangement to form an array with improved structural load distribution. The coupling member may attach to a slot in the frame at substantially any position along the length of the frame thereby enabling the interconnection of adjacent PV modules along both an x and y-axis. The system may further provide a rotating portion and locking portion for coupling to the frame attachment, mounting brackets for direct connection to a mounting surface, grounding teeth for the automatic creation of a reliable two axis grounding matrix, and a rapid twist-lock engagement means for reliably interlocking and aligning PV modules in the array. However, this embodiment includes a side-to-side arrangement to form an array and an additional groove/slot is formed on the frame to engage coupling member, which enables the interconnection of frames of adjacent PV modules. In addition, the parallel couplings are extended beyond corner regions of PV modules.
Various other mounting systems currently available are impossible to retrofit to existing roofs without cutting the shingles. The removal of a single PV panel from the PV array installed using some of these aforementioned mounting structures is difficult and can result in re-work thereby increasing labor and material costs. Some other systems do not allow for the capability to independently remove a single PV panel without deconstructing an entire row of PV panels, which significantly increases maintenance costs.
Therefore, there is a need for a rail-less roof mounting system that would provide a cost effective and improved means for PV module installations. Such a rail-less roof mounting system would provide an efficient means of installation that does not require any additional material or structure to support the rail-less roof mounting system. Such a rail-less roof mounting system would provide a corner-to-corner coupling arrangement enabling the bridging of a PV module corner directly with adjacent PV module corner. Such a needed device would provide reduced shipping and hardware costs, labor and installation time and cost; reduce the dead load on the roof structure along with design engineering costs; and hard and soft balance of system (BOS) cost. This rail-less roof mounting system would provide a single grounding lug and a single point of penetration with an elevated seal portion for waterproofing the roof structure. Such a rail-less roof mounting system would typically be designed for implementation on composition shingle roofs, tile roofs, metal roofs, low slope roofs, or any roof that would benefit from being waterproof. This mounting system would also provide simple grounding, wire management, and structural quality. This system would be simple, inexpensive, and lightweight. This system would provide an improved engineering design to accommodate high snow and wind loads. Further, this rail-less roof mounting system would allow an installer to easily work around roof obstructions like vents, skylights, and other roof protrusions. This system would also minimize the number of parts and tools needed to assemble and install the PV module. This rail-less roof mounting system would provide the ability to increase vertical leveling adjustability; to independently remove a single PV module without deconstructing an entire row of the PV array; and allow for easy mounting height adjustment after PV modules are installed. Finally, this rail-less roof mounting system would require less manpower to install and rework.